Objective

Our purpose was to determine the feasibility of selective photosensitization of vulvar condylomas by use of tropical application of 5-aminolevulinic acid.

Study design

In vivo fluorescence was assessed and biopsy specimens of condylomas were taken for fluorescence microscopy in 24 patients at different times after application of 2.5% 5-aminolevulinic acid ointment or 20% 5-aminolevulinic acid cream.

Results

Both in vivo fluorescence imaging and fluorescence microscopy showed selective fluorescence of condylomas of the labia minora and vestibule only within short time intervals, because fluorescence of poorly keratinized normal epithelium was induced by both 5-aminolevulinic acid formulations. In non-hair-bearing skin, lesional fluorescence remained highly selective. Fluorescence microscopy showed that 90 minutes after drug application peak selectivity in epithelial lesional fluorescence was significantly higher with 2.5% 5-aminolevulinic acid ointment (4.5 +/- 0.9) than it was with 20% cream (2.1 +/- 0.2).

Conclusion

Selective fluorescence of vulvar condyloma acuminatum can be induced by nonselective topical 5-aminolevulinic acid application. Studies evaluating selective photodynamic destruction of condylomas are justified.

Highly focused pulsed laser microbeams can be used to precisely dissect, inactivate, or perturb cells and subcellular targets. Here we introduce a new technique which employs pulsed microbeams to transiently permeabilize the plasma cell membrane and affect the delivery of molecules from the extracellular environment into the cell. This optically produced cell permeabilization can be applied using non-specific or specific modalities. In the non-specific modality, which we term 'optoporation', the pulsed microbeam is focused onto the glass coverslip on which the cells are plated. The generation of mechanical transients in connection with irradiation of the glass achieves molecular delivery to a number of cells proximal to the irradiation site. In the specific modality, termed 'optoinjection', the microbeam is focused direcly onto the plasma cell membrane and achieves molecular delivery into that cell alone. To quantify the irradiation geometry involved in these and other microbeam processes, as well as examine the possibility of certain non-linear effects, we have developed a system using photochromic polymer films to characterize microbeam propagation and its effects within microirradiated targets. These photochromic polymers confirm that the laser microbeam are indeed focused to submicron dimensions within the targets in our systems. In addition the behavior of such polymers at higher pulse energies and irradiances indicate that multiphoton absorption and/or plasma formation may mediate some laser microirradiation processes.

The purpose of this study was to determine whether in vivo fluorescence detection of protoporphyrin IX (PpIX) could be used to identify intraperitoneal micrometastases of epithelial ovarian carcinoma after application of 5-aminolevulinic acid (ALA). ALA was applied intraperitoneal at different concentrations (25, 50, and 100 mg/kg) and iv (100 mg/kg) to immunocompetent Fischer 344 rats bearing a syngeneic epithelial ovarian carcinoma. At different time intervals after ALA administration (1.5, 3, and 6 hr) the peritoneal cavity was illuminated with ultraviolet (uv) light. In vivo fluorescence of PpIX initially was determined by direct visualization. Subsequently ex vivo measurements were made with a slow-scan, thermoelectrically cooled CCD camera. Red in vivo fluorescence was observed in ovarian micrometastases smaller than 0.5 mm in 100% of the ALA-administered animals independent of time interval, drug concentration, or route of administration. The intensity of the fluorescence was concentration dependent as strong fluorescence was consistently found only above 25 mg/kg ALA. Ex vivo tumor to peritoneum fluorescence yield peaked 3 hr after administration of a 100 mg/kg intraperitoneal dose. Direct visualization of in vivo fluorescence after ALA application may improve the detection of intraperitoneal ovarian cancer micrometastases.

Microthermometric measurements on optically-trapped Chinese Hamster Ovary (CHO) cells and sperms cells are reported, using a non-invasive microfluorometric detection technique. Within an optical tweezer system that has been outfitted with a spectral fluorescence excitation and detection capability, the changes in temperature induced by the process of sample confinement by a focused laser beam has been quantified over micron-sized spatial regions of both motile and immotile cells. Our measurement technique is based on the use of environmentally sensitive fluorophores that can be incorporated into the cell membrane and used to sense local changes in temperature when the cell membrane is perturbed optically or via other environmental stress factors. Using a cw 1 .064 tm Nd:YAG laser for trapping CHO and human sperm cells, a temperature increase of -4°C per 100 mW laser power was observed. At this infrared wavelength, cellular heating as result of laser confinement appears to be mainly due to radiation absorption by water.